Revert "Disabled a couple of tests which are problem with the current 2.11.0-SNAPSHOT."

This reverts commit e17474c5ad00fe0557c19e7c433d4e313d873961.
Revert "Comment out test currently not compiling with 2.11.0-SNAPSHOT."

This reverts commit 8478e951d88e390f91a165ef14e3fb9d04d6ca6b.
Scala 2.11.0-SNAPSHOT support moved to its own branch.
Fixed Sized.unapplySeq for 2.11.0-SNAPSHOT and improve test.
Added support for compile-time testing of non-compilation.
Various mostly cosmetic tweaks.